You Shouldn't Add Oil To Your Pasta Water. Here's Why
If you're more of a home cook and less of a seasoned chef, you've probably at least once in your life followed the age-old technique of adding olive oil to your pasta water to prevent the noodles from sticking together. But as common as it is for pasta to stick together during the cooking process, the olive oil technique actually isn't the best solution. That's because, according to BuzzFeed, it's neither the texture of the pasta, nor what you add to the water, that causes the noodles to stick together. Rather, it's the cooking temperature.
Water that's boiling over high heat isn't the same as water boiling over low heat. BuzzFeed explains that you need your pasta water to be at a rolling boil in order for the pasta to cook properly and therefore not stick together. As Allrecipes further elaborates, a rolling boil is a more aggressive boil in which there are plenty of bubbles actively agitating the water. For certain recipes, including pasta, a rolling boil is necessary because any time you add ingredients to water, the temperature will drop slightly.
Why does pasta stick together after it's cooked?
Even noodles that have been cooked at a rolling boil still have the risk of sticking together. This is due to the fact that the cooking process releases the starches in the pasta, and the starches then cause the noodles to stick together once drained (via Cook's Illustrated). To prevent this, Eat This, Not That recommends boiling the pasta with more water. The higher the amount of water, the more diluted the starches will be, and as a result, there will be less sticking when you drain the pasta.
According to Insider, the sticking also depends on the quality of the pasta. Higher quality pasta is less prone to sticking because it contains more protein and gluten. Fortunately, there's a quick fix, which Insider explains is to coat the pasta in butter (not olive oil, as this will make it too slippery for sauce.) Just pay careful attention to both the amount and temperature of the water, and you'll keep any pasta stickiness at bay.